sysdeps/generic/dl-protected.h

   1 /* Support for STV_PROTECTED visibility.  Generic version.
   2    Copyright (C) 2021-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _DL_PROTECTED_H
  20 #define _DL_PROTECTED_H
  21
  22 static inline void __attribute__ ((always_inline))
  23 _dl_check_protected_symbol (const char *undef_name,
  24                             const struct link_map *undef_map,
  25                             const ElfW(Sym) *ref,
  26                             const struct link_map *map,
  27                             int type_class)
  28 {
  29   if (undef_map != NULL
  30       && undef_map->l_type == lt_executable
  31       && !(undef_map->l_1_needed
  32            & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)
  33       && (map->l_1_needed
  34           & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS))
  35     {
  36       if ((type_class & ELF_RTYPE_CLASS_COPY))
  37         /* Disallow copy relocations in executable against protected
  38            data symbols in a shared object which needs indirect external
  39            access.  */
  40         _dl_signal_error (0, map->l_name, undef_name,
  41                           N_("copy relocation against non-copyable protected symbol"));
  42       else if (ref->st_value != 0
  43                && ref->st_shndx == SHN_UNDEF
  44                && (type_class & ELF_RTYPE_CLASS_PLT))
  45         /* Disallow non-zero symbol values of undefined symbols in
  46            executable, which are used as the function pointer, against
  47            protected function symbols in a shared object with indirect
  48            external access.  */
  49         _dl_signal_error (0, map->l_name, undef_name,
  50                           N_("non-canonical reference to canonical protected function"));
  51     }
  52 }
  53
  54 #endif /* _DL_PROTECTED_H */